Fast Rotorcraft

Rotorcraft (sometimes referred to as rotary wing aircraft) are aircraft that use lift generated by rotors - these are assemblies comprising several rotor blades that revolve around a mast. Rotorcraft generally have one or more rotors to provide lift throughout the entire flight. A helicopter is a type of rotorcraft, but not all rotorcraft are helicopters.

In Clean Sky 2, two very different types of rotorcraft are planned - a tiltrotor and a compound rotor:

• A tiltrotor is an aircraft which generates both lift and propulsion using rotors that are mounted on swivelling engine pods or nacelles, usually mounted on a fixed wing – or are comprised of tilting rotors driven through gearboxes delivering the torque which comes from fixed engines. A tiltrotor can also have rotors that are mounted on fully tilting wings.
• A compound rotorcraft is an aircraft that combines a rotor with a supplementary form of propulsion - usually additional thrust engines or propellers.

The challenge in rotorcraft design is always to improve payload-lifting capability, reduce fuel burn and increase the vehicle's range – the traditional objectives in aeronautical design. But in Clean Sky 2, the two demonstrator aircraft planned have a very specific and novel feature: by combining forward “pull” or thrust with the vertical lift capability, both aircraft models will “bridge the gap” between traditional helicopters and fixed-wing aircraft. This means that due to their speed and range these novel vehicles will approach the mission capability of fixed-wing aircraft, yet also be able to take off and land vertically, and, importantly, “hover” in a fixed position over the ground when needed.

Also in Clean Sky 2, particular emphasis is placed on emissions and noise – for it is the noise nuisance level and the unique issue of taking off and landing in direct proximity to communities that can make rotorcraft unneighbourly.

Part of the challenge in tackling this noise issue is the fact that rotorcraft often operate in an unusual spectrum of different environments. A case in point is emergency service or medical evacuation helicopters that have to fly in and out of urban and densely populated areas, often following unique flight paths and landing into, and taking off from, the location needing the aircraft’s capability of “airlifting” (e.g. evacuating or rescuing) people.

The Fast Rotorcraft IADP consists of two concurrent concepts: the Tiltrotor demonstrator and the LifeRCraft Compound Rotorcraft demonstrator. Additionally, the Programme interfaces with other Clean Sky 2 Programme areas –– where there are mutual interests and opportunities, and synergy can be extracted from sharing research activity across the Programme to mutual benefit.

Examples in the technical area relate to the development of airframe, engine and system technologies covered in the respective Clean Sky 2 ITDs. But equally, these joint activities cover the methodology for technology evaluation of fast rotorcraft demonstrations and the Eco-Design concept implementation, along with the programme management activities for the Fast Rotorcraft IADP.

Concerning the methodology for technology evaluation, the activities will allow defining objectives and criteria adapted to the fast rotorcraft missions in line with the general TE approach for Clean Sky 2.

In addition, the tools used in Clean Sky 1 GRC1-GRC7 projects will be adapted and further developed in order to enable the assessment of conceptual rotorcraft models corresponding to the new configurations to be demonstrated in Clean Sky 2.

In respect of Eco-Design concept implementation, the activities will allow coordinating approaches and work plans in the two demonstration projects regarding the greening of rotorcraft production processes, ensuring complementarity of case studies. The general Life Cycle Assessment approach will be coordinated with the participants of the Eco-Design TA.

What is particularly significant here is that these two demonstrator fast rotorcraft in the Clean Sky 2 programme not only introduce new technologies – these aircraft are also pioneers of a new segment within the rotorcraft category, bringing completely new capabilities. For example, the high speed of the LifeRCraft, in a medevac situation, would enable the rotorcraft to reach offshore oil or wind-farm platforms within the "golden hour" - the critical first 60 minutes following a medical emergency event when paramedic access to those in need can make all the difference to patient recovery.